Acoustic wave devices are employed in filters and duplexers for wireless communication devices such as mobile phone terminals. There has been known surface acoustic wave (SAW) devices including an Interdigital Transducer (IDT) having a pair of comb-shaped electrodes located on a piezoelectric substrate as the acoustic wave device. Additionally, to improve power durability, there has been known serially dividing a single SAW device as disclosed in Japanese Patent Application Publication Nos. 2001-285025 and 2001-24471. Additionally, to improve the confinement of the surface acoustic wave in the resonator, there has been known providing dummy electrode fingers between electrode fingers in each of the comb-shaped electrodes as disclosed in Japanese Patent Application Publication No. 2003-198317. Alternatively, there has been known a multimode type surface acoustic wave device using waves in different modes, or connecting the multimode type surface acoustic wave devices in multiple stages as disclosed in Patent Application Publication Nos. 5-129884, 6-37585, 10-32463, 2000-323935, and 2001-127587.
When a single acoustic wave device is serially divided to improve power durability, the device increases in size.